Update index.html

Force SSL pour obliger la navigations en HTTPS
Ajout en code XML 
<?xml version="1.0" encoding="UTF-8" ?>

<routes xmlns="http://symfony.com/schema/routing"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://symfony.com/schema/routing http://symfony.com/schema/routing/routing-1.0.xsd">

    <route id="secure" pattern="/secure">
        <default key="_controller">AcmeDemoBundle:Main:secure</default>
        <requirement key="_scheme">https</requirement>
    </route>
</routes>